From what I have seen with my ducks, things can get hormonal, and then there are no good reasons.

I would get the duck to a safe place, make sure any other fowl are safe from the turkey, and get the duck into a lukewarm tub of water, no soap. Take a look, check for injuries, under wings, around vent. Check her eyes, make sure she's not bleeding.

I would mist her heat with some saline solution or Vetericyn spray, and keep her in a safe clean quiet place with water and food overnight. She may be fine by morning.